<template>
  <div class="container">
    <h2>Minio 上传示例</h2>
    <el-upload
      class="upload-demo"
      ref="upload"
      action="https://jsonplaceholder.typicode.com/posts/"
      :on-remove="handleRemove"
      :on-change="handleFileChange"
      :file-list="uploadFileList"
      :show-file-list="false"
      :auto-upload="false">
      <el-button slot="trigger" type="primary" plain>选择文件</el-button>
      <el-button style="margin-left: 10px;" type="success" @click="handleUpload" plain>上传</el-button>
      <el-button type="danger" @click="clearFileHandler" plain>清空</el-button>
    </el-upload>
    <!-- 文件列表 -->
    <div class="file-list-wrapper">
      <el-collapse>
        <el-collapse-item v-for="(item, index) in uploadFileList" :key="index">
          <template slot="title">
            <div class="upload-file-item">
              <div class="file-info-item file-name">文件名：{{ item.name }}</div>
              <div class="file-info-item file-size">文件大小：{{ item.size | transformByte }}</div>
              <div class="file-info-item file-progress">
                <span class="file-progress-label">文件进度：</span>
                <el-progress :percentage="item.uploadProgress" class="file-progress-value"/>
              </div>
              <div class="file-info-item file-size"><span>状态：</span>
                <el-tag v-if="item.status === '等待上传'" size="medium" type="info">等待上传</el-tag>
                <el-tag v-else-if="item.status === '校验MD5'" size="medium" type="warning">校验MD5</el-tag>
                <el-tag v-else-if="item.status === '正在上传'" size="medium">正在上传</el-tag>
                <el-tag v-else-if="item.status === '上传成功'" size="medium" type="success">上传完成</el-tag>
                <el-tag v-else size="medium" type="danger">上传错误</el-tag>
              </div>
            </div>
          </template>
          <div class="file-chunk-list-wrapper">
            <!-- 分片列表 -->
            <el-table
              :data="item.chunkList"
              max-height="400"
              style="width: 100%">
              <el-table-column
                prop="chunkNumber"
                label="分片序号"
                width="180">
              </el-table-column>
              <el-table-column
                prop="progress"
                label="上传进度">
                <template v-slot="{ row }">
                  <el-progress v-if="!row.status || row.progressStatus === 'normal'" :percentage="row.progress"/>
                  <el-progress v-else :percentage="row.progress" :status="row.progressStatus" :text-inside="true"
                               :stroke-width="16"/>
                </template>
              </el-table-column>
              <el-table-column
                prop="status"
                label="状态"
                width="180">
              </el-table-column>
            </el-table>
          </div>

        </el-collapse-item>
      </el-collapse>
    </div>
  </div>
</template>

<script>
import SparkMD5 from 'spark-md5'
import axios from 'axios'
import {getFileUploadUrls, mergeUpload} from '@/api/file/sharding'

const FILE_UPLOAD_ID_KEY = 'file_upload_id'
const chunkSize = 10 * 1024 * 1024
let currentFileIndex = 0
const FileStatus = {
  wait: '等待上传',
  getMd5: '校验MD5',
  uploading: '正在上传',
  success: '上传成功',
  error: '上传错误'
}
export default {
  data() {
    return {
      changeDisabled: false,
      uploadDisabled: false,
      // 上传并发数
      simultaneousUploads: 3,
      uploadIdInfo: null,
      uploadFileList: [],
      retryList: []
    }
  },
  methods: {
    handleUpload() {
      const self = this
      const files = this.uploadFileList
      if (files.length === 0) {
        this.$message.error('请先选择文件')
        return
      }
      // 当前操作文件
      const currentFile = files[currentFileIndex]
      currentFile.status = FileStatus.getMd5
      // 1. 计算MD5
      this.getFileMd5(currentFile.raw, async (md5) => {
        // 2. 正在创建分片
        let fileChunks = self.createFileChunk(currentFile.raw, chunkSize)
        let param = {
          originalFileName: currentFile.name,
          fileSize: currentFile.size,
          chunkSize: chunkSize,
          fileMd5: md5,
          contentType: 'application/octet-stream'
        }
        // 3. 获取上传url
        let shardingUploadResult = await self.getFileUploadUrls(param)
        self.uploadIdInfo = shardingUploadResult
        let uploadUrls = shardingUploadResult.uploadUrls
        if (fileChunks.length !== uploadUrls.length) {
          self.$message.error('文件分片上传地址获取错误')
          return
        }
        // self.$set(currentFile, 'chunkList', [])
        fileChunks.map((chunkItem, index) => {
          currentFile.chunkList.push({
            chunkNumber: index + 1,
            chunk: chunkItem,
            uploadUrl: uploadUrls[index],
            progress: 0,
            status: '—'
          })
        })
        let tempFileChunks = []
        currentFile.chunkList.forEach((item) => {
          tempFileChunks.push(item)
        })
        currentFile.status = FileStatus.uploading
        // 5. 上传
        await self.uploadChunkBase(tempFileChunks)
        console.log('上传完成')
        // 6. 合并文件
        const mergeResult = await self.mergeFile({
          uploadId: self.uploadIdInfo.uploadId,
          fileName: self.uploadIdInfo.fileName,
          md5: md5
        })
        currentFile.status = FileStatus.success
        console.log('文件访问地址：' + mergeResult.fileUrl)
        self.$message.success(`上传成功，文件地址：${mergeResult.fileUrl}`)
      })
    },
    clearFileHandler() {
      this.uploadFileList = []
      this.uploadIdInfo = null
    },
    handleFileChange(file, fileList) {
      this.uploadFileList = fileList
      this.uploadFileList.forEach((item) => {
        // 初始化自定义属性
        this.initFileProperties(item)
      })
    },
    initFileProperties(file) {
      file.chunkList = []
      file.status = FileStatus.wait
      file.progressStatus = 'warning'
      file.uploadProgress = 0
    },
    handleRemove(file, fileList) {
      this.uploadFileList = fileList
    },
    /**
     * 分片读取文件 MD5
     */
    getFileMd5(file, callback) {
      const blobSlice = File.prototype.slice || File.prototype.mozSlice || File.prototype.webkitSlice
      const fileReader = new FileReader()
      // 计算分片数
      const totalChunks = Math.ceil(file.size / chunkSize)
      console.log('总分片数：' + totalChunks)
      let currentChunk = 0
      const spark = new SparkMD5.ArrayBuffer()
      loadNext()
      fileReader.onload = function (e) {
        try {
          spark.append(e.target.result)
        } catch (error) {
          console.log('获取Md5错误：' + currentChunk)
        }
        if (currentChunk < totalChunks) {
          currentChunk++
          loadNext()
        } else {
          callback(spark.end())
        }
      }
      fileReader.onerror = function () {
        console.warn('读取Md5失败，文件读取错误')
      }

      function loadNext() {
        const start = currentChunk * chunkSize
        const end = ((start + chunkSize) >= file.size) ? file.size : start + chunkSize
        // 注意这里的 fileRaw
        fileReader.readAsArrayBuffer(blobSlice.call(file, start, end))
      }
    },
    /**
     * 文件分片
     */
    createFileChunk(file, size = chunkSize) {
      const fileChunkList = []
      let count = 0
      while (count < file.size) {
        fileChunkList.push({
          file: file.slice(count, count + size),
        })
        count += size
      }
      return fileChunkList
    },
    uploadChunkBase(chunkList) {
      const self = this
      let successCount = 0
      let totalChunks = chunkList.length
      return new Promise((resolve, reject) => {
        const handler = () => {
          if (chunkList.length) {
            const chunkItem = chunkList.shift()
            // 直接上传二进制，不需要构造 FormData，否则上传后文件损坏
            axios.put(chunkItem.uploadUrl, chunkItem.chunk.file, {
              // 上传进度处理
              onUploadProgress: self.checkChunkUploadProgress(chunkItem),
              headers: {
                'Content-Type': 'application/octet-stream'
              }
            }).then(response => {
              if (response.status === 200) {
                console.log('分片：' + chunkItem.chunkNumber + ' 上传成功')
                successCount++
                // 继续上传下一个分片
                handler()
              } else {
                console.log('上传失败：' + response.status + '，' + response.statusText)
              }
            }).catch(error => {
              // 更新状态
              console.log('分片：' + chunkItem.chunkNumber + ' 上传失败，' + error)
              // 重新添加到队列中
              chunkList.push(chunkItem)
              handler()
            })
          }
          if (successCount >= totalChunks) {
            resolve()
          }
        }
        // 并发
        for (let i = 0; i < this.simultaneousUploads; i++) {
          handler()
        }
      })
    },
    getFileUploadUrls(fileParam) {
      return getFileUploadUrls(fileParam)
    },
    saveFileUploadId(data) {
      localStorage.setItem(FILE_UPLOAD_ID_KEY, data)
    },
    /**
     * 合并文件
     */
    mergeFile(file) {
      const self = this
      let param = {
        uploadId: file.uploadId,
        fileName: file.fileName,
        fileMd5: file.md5,
      }
      return new Promise((resolve, reject) => {
        mergeUpload(param).then(response => {
          let data = response
          file.status = FileStatus.success
          resolve(data)
        }).catch(error => {
          self.$message.error('合并文件失败：' + error)
          file.status = FileStatus.error
          reject()
        })
      })
    },
    /**
     * 检查分片上传进度
     */
    checkChunkUploadProgress(item) {
      return p => {
        item.progress = parseInt(String((p.loaded / p.total) * 100))
        this.updateChunkUploadStatus(item)
      }
    },
    updateChunkUploadStatus(item) {
      let status = FileStatus.uploading
      let progressStatus = 'normal'
      if (item.progress >= 100) {
        status = FileStatus.success
        progressStatus = 'success'
      }
      let chunkIndex = item.chunkNumber - 1
      let currentChunk = this.uploadFileList[currentFileIndex].chunkList[chunkIndex]
      // 修改状态
      currentChunk.status = status
      currentChunk.progressStatus = progressStatus
      // 更新状态
      this.$set(this.uploadFileList[currentFileIndex].chunkList, chunkIndex, currentChunk)
      // 获取文件上传进度
      this.getCurrentFileProgress()
    },
    getCurrentFileProgress() {
      const currentFile = this.uploadFileList[currentFileIndex]
      if (!currentFile || !currentFile.chunkList) {
        return
      }
      const chunkList = currentFile.chunkList
      const uploadedSize = chunkList.map((item) => item.chunk.file.size * item.progress).reduce((acc, cur) => acc + cur)
      // 计算方式：已上传大小 / 文件总大小
      let progress = parseInt((uploadedSize / currentFile.size).toFixed(2))
      currentFile.uploadProgress = progress
      this.$set(this.uploadFileList, currentFileIndex, currentFile)
    }
  },
  filters: {
    transformByte(size) {
      if (!size) {
        return '0B'
      }
      const unitSize = 1024
      if (size < unitSize) {
        return size + ' B'
      }
      // KB
      if (size < Math.pow(unitSize, 2)) {
        return (size / unitSize).toFixed(2) + ' K';
      }
      // MB
      if (size < Math.pow(unitSize, 3)) {
        return (size / Math.pow(unitSize, 2)).toFixed(2) + ' MB'
      }
      // GB
      if (size < Math.pow(unitSize, 4)) {
        return (size / Math.pow(unitSize, 3)).toFixed(2) + ' GB';
      }
      // TB
      return (size / Math.pow(unitSize, 4)).toFixed(2) + ' TB';
    }
  }
}
</script>

<style>
.container {
  width: 1000px;
  margin: 0 auto;
}

.file-list-wrapper {
  margin-top: 20px;
}

h2 {
  text-align: center;
}

.file-info-item {
  margin: 0 20px;
}

.upload-file-item {
  display: flex;
}

.file-progress {
  display: flex;
  align-items: center;
}

.file-progress-value {
  width: 250px;
}

.uploader-example {
  width: 880px;
  padding: 15px;
  margin: 40px auto 0;
  font-size: 12px;
  box-shadow: 0 0 10px rgba(0, 0, 0, .4);
}

.uploader-example .uploader-btn {
  margin-right: 4px;
}

.uploader-example .uploader-list {
  max-height: 440px;
  overflow: auto;
  overflow-x: hidden;
  overflow-y: auto;
}
</style>
